Initial support for completing selector parts. When user types map at: 1 ifA then the completer also offers to complete `ifAbsent:`, `ifAbsentPut:` ... in addition to SmallInteger methods.

Fix for Smalltalk node finder. Now, comments array contain offsets of start and end of a comment (not start and length, as it used to contain).

Added a little help text to completion view. Currently it shows some help text what to do and inferred receiver type when completing message selector.

Yet another fix in completion view. First, pre-select item that matches typed prefix exactly, if none, filter using similarity matching. If none matches exactly, do not autocomplete.

Fix in completion - do not autocomplete when prefix does not match selected item exactly.

Fixes issue #4 - Use levenshtein distance when computing prefix-based selector completion. Levenshtein distance is used for all prefixes longer then 4 characters. The limit is set to 15.

Bugfix in EditSupport textView instvar was accidentically overwritten with codeView.

Support for Tab in code completion. Pressing Tab when code completion window is open completes longes common prefix of items matching already typed text. If no text can be completed, flashes the completion popup.

Fixed issue #3

Allow lint window to be closed by pressing escape.