Interactive search improvements.

- exact word interactive search commands
- highlight secondary matches
- next, previous from within interactive commands
Remove accidental line dup
Revert unintentional rename of buffer-repeat-search
Fix buffer.[r]find negative init; update spec, doc
Add new 'terminal' markup parser

For parsing terminal output. Primarily deals with color sequences,
but also handles BS characters properly.
cdefs: Fixup pasting error.
ProcessBuffer: Parse terminal output (ANSI colors, etc)
Add default base color styles
Use base color styles when defining ansi styles
Update Changelog with note about ANSI color support
Improve buffer.md doc for find, rfind
Merge pull request #34 from shalabhc/interactive-search

Interactive search improvements
External command input: Support cd using bare directories
Add new COMPOSITIONTHICK highlight type
Update search highlights to stand out more
Ruby: Properly lex bare general delimited strings
VI: Bind `?` to `buffer-search-backward`
Add buffer-close name for close command

The latter is now an alias for the former.
ProcessMode: Don't highlight current line by default
external command input: Support completion of absolute and ~/ paths