Added ability to ignore specific paths for analyzer (closes #3).
analyzeall: Don't write masks back into specs

Doing so renders the original specs invalid, resulting in subsequent
calls of analyzeProject() not ignore the original specs.
This also makes masking the specs an increasingly complex operation
as `specs` grows, rendering subsequent uses of analyzeProject()
take exponentially more time up to the point of unusability.

This commit solves this problem by creating a local `masks` table,
 which the masks are written to and read from.
Renamed the MCServer API file.

This corresponds to commit mc-server/MCServer@f38a009b3cc5caf25d11496fda5caf75531127d0.
Added 'Open image file' plugin.
Added 'Filetree one-click activation' plugin.
Renamed filetree one-click plugin with a better name.
Updated luadist to allow `root` option to be specified in the config file.