Added a number of enhancements to an already very useful package

[lowegreg]

Not sure it this repo is still being maintained, but I thought I would pass along my own enhancements for others to use.

• Auto sort on load (thanks to https://github.com/brianjcohen)
• Group by symbol within the sort feature
• Highlight symbol parent when current element is collapsed
• Incorporated Tree View events to initialize symbol list prior to file being active
• Condensed some spacing elements.

[nicolashainaux]

Yeah, well I'm been extremely busy but things should be better soon... I'll certainly check and merge any suggested enhancements asap, I just need some days/weeks but I'll do it :) Many thanks for this!

[nicolashainaux]

Hello,

Things are still not really better but I finally took some time to review the suggested changes. I had to correct some bugs so I cannot merge the PR, but I include the changes in the next release and of course credit you in the README. (By the way, I don't know why you would delete it?).