feat(fileTree): satisfactory tree styling and selection characteristics

- Clicking anywhere along the y-axis of the file tree selects the entry in the same row (even if the label is not clicked)
- Add full row selection and hover styles
- Add font-awesome icons to represent various file types in the tree.
- A little CSS *bam* from the Style Weasel.
refactor(fileTree): resize canvas when splitter changes
refactor(ui): more ui cleanup for file tree and editor

- Remove custom colors from tmx files in tree
- Use bold to indicate tmx files
- Use standard file/folder icons from font-awesome for the tree