Add support for 3 char hex, hsl(a), and css colors.
Add support for specifying default import paths and files.

Additionally checks if current file is in a /style/ or /styles/ directory for more robust default color importing support.

Fixes issue with doing a simple vim split with no other file.
Scope variables to windows instead of buffers.
Detect first entry of a new window in the case a read was not performed.

only imports .scss files if you open a .scss file, etc.
resolves bugs when file is found matching your import name, but has a wrong suffix
this seems like a general enough use case, but if we are abiding by ruby's Dir.glob restrictions, we can't use a restrictive regex to only allow /\.scss|\.sass|\.less/

Fixes some issues when closing a buffer and then opening the same file
Adds hook to run on reading new buffers

Instead of calling clearmatches() which clears all matches added with matchadd() we instead keep a list of matches we have added and just clear those on (re)save.

Additionally fixed typo where we were adding unnecessary 'placeholder' matches, this will speed up the plugin the more colors you use that are unassigned to variables.

previously, when saving a file repeatedly, we would re-parse everything and keep adding duplicate matches which would slow down vim after many saves

• clears matches before running each time
• doesn't redefine a highlight group
• doesn't re-add rgb, rgba, or hex color literal mathes

Should still work the same as previous version
Cleaned up and encapsulated file import logic
Squeezes adjacent slashes (/) in globbing (no difference, but cleaner)