VDR EPGFixer Plugin

New features:
- Enable JIT compiling in PCRE if supported.
- Support for channel intervals for channel numbers.
- Support search-and-replace using Perl-style 's///' operator.
- Support Perl-style modifiers when using 's///' or 'm//' operators.
- Support stripping control characters from EPG data as in VDR-1.7.31.

Bug fixes:
- Fix appending and prepending to empty EPG fields.