Install regex header if enabled
Merge branch 'develop' of github.com:ellzey/libevhtp into develop

Conflicts:
	CMakeLists.txt
Removed unused code.
put include files back in base
v1.2.1, see ChangeLog for details.
Merge branch 'release/1.2.1'
Merge branch 'release/1.2.1' into develop
blerp
v1.2.2 - hotfix
Merge branch 'release/1.2.2'
Merge branch 'release/1.2.2' into develop
Port to MinGW
Added evhtp_disable_100_continue() which informs evhtp to not send a 100 continue response.
Release v1.2.3, see ChangeLog for details.
Merge branch 'release/1.2.3'
Merge branch 'release/1.2.3' into develop
run on_headers_begin if request type is response (this happens when a 100 continue type thing happens).
v1.2.4, see ChangeLog for details.
Merge branch 'release/1.2.4'
Merge branch 'release/1.2.4' into develop