Updates to Filter Extension for CQL2 (#225)

* numerous updates to CQL2 definitions

* few more basic-cql2 replacements

* update cql2 prefixes

* add between and like

* fix quotes in cql text examples

* add filter-lang to examples

* remove Filter Ext Case-sensitive Comparison class

CHANGELOG.md

@@ -16,6 +16,26 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - Limit parameter semantics now match OAFeat. Previously, the behavior was not precisely defined.
+- Filter Extension updates to align with changes to OAFeat CQL2 spec
+  - Updated all "CQL" usages to "CQL2"
+  - Most conformance class URIs are now prefixed with `http://www.opengis.net/spec/cql2/` instead
+    of `http://www.opengis.net/spec/ogcapi-features-3/`
+  - Conformance classes `http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/basic-cql`, 
+    `http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/cql-text`, and
+    `http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/cql-json` have had `cql` replaced
+    with `cql2` (in addition to the prefix change) to
+    become `http://www.opengis.net/spec/cql2/1.0/conf/basic-cql2`,
+    `http://www.opengis.net/spec/cql2/1.0/conf/cql2-text`, and
+    `http://www.opengis.net/spec/cql2/1.0/conf/cql2-json`
+  - Significant changes to CQL2 JSON format, now using `op` and `args` structure
+  - Spatial operator `INTERSECTS` is now `S_INTERSECTS`
+  - Temporal operator `ANYINTERACTS` is now `T_INTERSECTS`
+  - Updated Example 3 (now Example 5) to make it clear that property to property comparisons require the
+    Property-Property Comparisons conformance class
+  - The CQL2 Case-insensitive Comparison 
+    (`http://www.opengis.net/spec/cql2/1.0/conf/case-insensitive-comparison`) conformance class
+    that adds UPPER/LOWER terms or function CASEI for case-insensitive comparison has not been added
+    to this spec yet, since the definition in CQL2 is in flux.
 - `service-desc` endpoint may return any service description format, typically a 
   machine-consumable one (previous restricted required to be OpenAPI 3.0 JSON)
 - `service-doc` endpoint may return any service description format, typically a

extensions.md

@@ -70,18 +70,19 @@ the service supports. This are listed at the top of each extension description,
   - <https://api.stacspec.org/v1.0.0-beta.5/ogcapi-features#fields>
 - [Filter](item-search/README.md#filter)
   - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/filter>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/basic-cql>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/basic-cql2>
   - <https://api.stacspec.org/v1.0.0-beta.5/item-search#filter:item-search-filter>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/cql-text>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/cql-json>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/advanced-comparison-operators>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/basic-spatial-operators>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/spatial-operators>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/temporal-operators>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/functions>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/arithmetic>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/array-operators>
-  - <http://www.opengis.net/spec/ogcapi-features-3/1.0/conf/property-property>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/cql2-text>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/cql2-json>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/advanced-comparison-operators>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/basic-spatial-operators>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/spatial-operators>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/temporal-operators>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/functions>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/arithmetic>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/array-operators>
+  - <http://www.opengis.net/spec/cql2/1.0/conf/property-property>
+  <!-- - <http://www.opengis.net/spec/cql2/1.0/conf/case-insensitive-comparison> -->
 - [Context](item-search/README.md#context)
   - <https://api.stacspec.org/v1.0.0-beta.5/item-search#context>
   - <https://api.stacspec.org/v1.0.0-beta.5/ogcapi-features#context>