Add include compiler directive

[Former user]

Many frameworks (like JCL) and developers use include files for various reasons.

Mostly for Definitions. Please support {$I file.inc} includes do all {$DEFINE XXX} are supported, or better the content of the include file is seen as part of the actual file.

[George Bakhtadze]

Include file with defines already supported. All code branches which uses conditional defines after {$I file.inc} should be highlighted and parsed according to conditionals defined in file.inc. If it's not it's a bug - please report with minimal source to reproduce.