Tclint

- Adds `extensions` config option for specifying which files to lint when searching a directory
- If unspecified, the same files are linted as before, with the addition of `.upf` files
- Installing multiple plugins with the same name is now an error

- Changes `exclude` config option to support gitignore pattern format (https://git-scm.com/docs/gitignore)
- Note: this is a subtle breaking change. You should review your exclude patterns to ensure they still match what you intend, but a quick way to match previous functionality is to prepend all your exclude entries with `/`.
- Adds `unbraced-expr` check for unbraced expressions containing substitutions
- Adds `--show-categories` feature that causes `tclint` to display a category tag before violation rule ID
- Fixes bug related to plugins with duplicate names

- Adds `spaces-in-braces` check for spacing of braces around expression or script arguments
- Adds spacing within parentheses to `expr-format` check
- Improves some syntax error messages
- Adds extra-verbose debug output with `-dd`
- Adds support for reading input from stdin with `tclint -`
- Fixes bug reading from character devices such as `/dev/stdin`

- Adds initial expression formatting checks
- Includes operand/operator spacing, function call formatting
- Adds check for consistent spacing between line contents and newline escapes
- Fixes bug where multi-line conditionals in `if`, `while`, etc. could cause spurious indentation errors in rare cases
- Fixes bug where command argument spacing wasn't checked on continuation lines
- Note: this may flag additional `spacing` violations on codebases where these were previously missed

The parser is now much more complete!

- Complete parsing of arguments interpreted as scripts for just about all built-in commands
- `package ifneeded` and `after cancel` are the only exceptions
- Implement expression parsing
- This will catch syntax errors and errors in command substitutions within expressions
- Style checking for expressions coming in a future release!
- Miscellaneous bug fixes

Relatively big release!

- Add new checks:
- Too many consecutive blank lines (5)
- Redefined built-ins
- Add `style.indent-namespace-eval` config option to waive extra indentation level for `namespace eval` blocks
- Add beta "command plugin" feature