Refactored completion request creation

- OmniCompleter is now more similar to other Completers.
- CompletionRequest doesn't store start_column anymore.
- Calling BuildRequestData only once per request.
Fix missing param in OmniCompletionRequest
Removing erroneous whitespace
Updating to latest ycmd
Better detection of shortmess 'c' availability

Also noting that the annoying messages during completion go away with Vim
7.3.314.

Related to #642.
Minor rewording in README
Updating to latest ycmd

Top-level 'filetypes' property not needed in request data anymore.
Updating to latest ycmd
Handle libclang diags for line_num 0

Fixes #978
Updating to latest ycmd
Update to latest ycmd

Upstream completions API changed.
Updating to latest ycmd

Diagnostic & completion 'kind' changed in the REST API.
Updating vimdoc from readme

Fixes #1009
Bundle name is deprecated.

Bundle name is not used anymore in the Vundle plugin. Use Plugin instead.
Change reference of Bundle to Plugin in the docs
Change reference of Bundle to Plugin in the docs
Merge pull request #1020 from adelarsq/patch-1

Bundle name is deprecated.