added pid & tid filtering feature

[salsal97]

This PR adds the strace filter that let's you filter by thread ID or process ID (upto 10 at a time)
to make your output more relevant

[vtikoo]

As syscall entry and exit hooks are hot code paths, thinking about performance impact.

Checking whether current thread/process is whitelisted is a linear scan of array of ints. In the worst case this is a scan of 100 integers, which would span atleast 6 cache lines.
The syscall include and exclude filters are single word lookups. Checking whether the syscall number snum is in either list, requires only looking at trace[snum].

An alternative is encoding the tid filter as a bit vector. The max number of threads we support is 1024, so that would be a bit vector atleast 128 bytes long. We could potentially also leverage the fact that our tid/pid generation algorithm starts from 101. So tid 101 could be the 1st bit of the bit vector and so on.

Having said that, if memory is not the bottleneck then this optimization might not be as useful.