Add regexp module API with a first module : PCRE

Current API only support following function :
  - compile
  - exec
  - match

And only support full string for matching
Add partial input regexp, we called it feed()
Remove string size argument from regexp call

Add a generic typemap for (const char *STRING, size_t SIZE) from psdesse idea
Fix indentation problem (spaces instead of tab)
Add regexp on vbuffer
Rework regexp module to add regexp_ctx

This allow one compiled regexp to be used on multiple stream with feed
Enhance regexp module

Add ref count on regexp
Add auto growth of pcre workspace
Fix pcre module error handling
Add regexp test going throught every available module
Add comment
Fix pcre module memory leak
Use module from env vars in regexp unit test
Fix unit test names
Rename regexp re:exec() in re:match() in lua
Fix memory leak on regexp module load
Cosmetics
Add PCRE workspace growth limit
Fix regexp feed return
Fix vbfeed vbuffer iteration
Add regexp_module_release function