search: Adjust log levels for max search depth

When a user has specified a specific max search depth (--depth), it is
reasonable to assume that they are aware of it. In this case, it should
suffice to output this information on the debug level.

Relatedly, it is not (in my opinion) an error to exceed the max search
depth, since the program is designed that way. I've lowered it to a
warning.

This increases, in my experience, the user friendliness of the --depth
option, since it outputs a lot less noise.
Fix win32 build
Auto enable color when CMDER is running
Merge pull request #500 from larsch/detect-cmder

Auto enable color when CMDER is running
Merge pull request #398 from catharsis/search-depth-noise

search: Adjust log levels for max search depth
Add dir name to ignores. Fix bug where multiple paths could cause root_ignores to leak memory or behave weirdly.
Separate ignores that start with a slash from the rest. We'll need to search them differently.
Fix segfault. Initialize slash_* and search some of the slash patterns.
Merge pull request #495 from mattn/win32fix

Fix win32 build
--vimgrep option added, reporting every match on the line, like :vimgrep /pattern/g
Add file types completion
Remove unused if statement
Merge pull request #504 from inside/vimgrep

--vimgrep option added, reporting every match on the line
refactor language count
remove null object
Add tests for some ignore issues

There are many other uncaught bugs, but this catches bugs corresponding
to a few open issues
Merge pull request #508 from rphillips/fixes/langs-count

refactor language count
Merge branch 'master' into deep_ignores
Merge remote-tracking branch 'origin/ignore-test-cases' into deep_ignores
Add abs_path to ignore struct.