Merge pull request #188 from cgzones/os_regex_unittests

os_regex unit tests
[os_regex] convert octal chars to decimal ones in regex maps, because octal values grater than \177 = 128 causing conversion warnings
[os_regex] fix compiler warnings
[os_regex] remove macro definitions already defined in os_regex.h
[os_regex] update makefile
[os_regex] fix compiler warnings about const discarding
[os_regex] lower scope of variables, suggested by cppcheck
[os_regex] size_t is always greater equal 0
[os_regex] init matching function pointer of OSMatch with NULL
[os_regex] make pattern const in matching functions
[os_regex] free OSMatch elements independent from each other
[os_regex] remove solved todo
[os_regex] simplification
[os_regex] check for memory error before doing something else
[os_regex] make local functions static
[os_regex] make pattern const in _OS_Regex
[os_regex] OSRegex: free flags independent from patterns
[os_regex] OS_WordMatch,OS_StrIsNum,OS_StrHowClosedMatch,OS_StrBreak: make arguments const
OS_StrHowClosedMatch: change result tpye to size_t
[os_regex] rewrite OS_StrStartsWith, so that the length of the pattern does not need to be computed
[os_regex] declare OSRegex.prts_closure as const