Introduce company-ghc-hoogle-command

Used to specify hoogle command name.
Use "hoogle" if haskell-hoogle-command is nil
Add scan module related stuff

* Make company-ghc-scan-modules interactive so that user can call it.
* Add turn ON/OFF functions for autoscan, which adds/removes
  company-ghc-scan-modules function to/from after-save-hook.
* Add configuration to enable autoscan at init.
Add note for auto scan module
Use magnars reporter
Change company-ghc-autoscan-after-save to company-ghc-autoscan

Now if it it nil, scan module does not run at init also.
Update document for company-ghc-autoscan
Bump version to v0.1.2
Add diagnostic function

Interative function, company-ghc-diagnose, shows scanned modules, their
aliases and candidates in the current buffer.
Show auto scan status in diagnostic info
Refine diagnostic info layout
Describe company-ghc-diagnose function

Remove TODO section, there is no plan to support haskell-docs now.
GitHub issue will be used for TODO.
Fix compile time warning related to cl-dolist
Bump version to v0.1.3
Add more incomplete import test cases
Handle incomplete import declaration

Unmatched parenthesis, import at end of buffer cases are handled.

Bump version to v0.1.4.
Describe ghc-mod configuration notes
Add ghc-boot status check in company-ghc-diagnose
Call ghc-load-module instead of ghc-load-merge-modules

This can fix completion from locally defined modules.

Bump version to v0.1.5.
Change to use company-dabbrev-code in example