Add "Parsing Modes" to disable compiling

[bscan]

For security reasons, some people may want to disable compilation, but still use the tagger based autocompletion, Perl::Critic, Perl::Tidy, etc. Add a parsing mode setting, which will currently include perl -c and no compiling, but should also include a "tagging" based method in the future. This can probably be done by adding a BEGIN{exit(0)} at the top of the Perl script or similar technique.

[mrsdizzie]

This would be nice! I have a large project that uses a lot of modules I don't have installed locally and I get compilation aborted type errors if trying to use the language server while editing files locally.