Merge pull request #82 from racklin/bugfix/subpos

Improving assumptions about offset parameter in StrposOptimizer.
Merge pull request #83 from racklin/enhancement/trim_support_2param

Improving trim/ltrim/rtrim supports charlist parameter .
Merge pull request #84 from racklin/enhancement/exists

Added some exists check optimizers.
#74 TypeOf fixes and added support for native types
Merge pull request #85 from zaets28rus/74_issue

#74 TypeOf fixes and added support for native types
Reusing temporary variables in array definition [ci skip]
Initial implementation for internal method calls [ci skip]
Merge remote-tracking branch 'upstream/master'

Signed-off-by: Rack Lin <racklin@gmail.com>

Conflicts:
	ext/test/strings.c