Implemented `write` command.

`jekyll write [type]` creates a new post, page, or draft depending on [type]. It supports option for --path, --title, and --ext.

See `jekyll help write`.
fixup! Implemented `write` command.
use binary mode when writing file.
Cleaned up the deprecator a little
Print warning when `paginate` is set to `true`.

Related to #1105.

Sample output:
~/code/jekyll/tsite$ ../bin/jekyll build --trace
Configuration file: /Users/parker/code/jekyll/tsite/_config.yml
    Config Warning: The `paginate` key must be a positive integer or nil. It's currently set to 'true'.
            Source: /Users/parker/code/jekyll/tsite
       Destination: /Users/parker/code/jekyll/tsite/_site
      Generating... done.
paginate option cannot be 0.
Add test for Configuration#fix_common_issues
Merge pull request #1364 from koron/write-in-binary-mode

use binary mode when writing file.
Update history to reflect merge of #1364
Add -D short-form switch for drafts

Add -D short-form switch for the drafts option, to compliment --drafts
Merge pull request #1394 from catsby/drafts_flag

Add -D short-form switch for drafts
Update history to reflect merge of #1394
Merge pull request #1390 from mojombo/better-errors

Catch and fix (somehow) common configuration errors
Update history to reflect merge of #1390
Merge branch 'write_command' of git://github.com/Schoonology/jekyll into write-command

* 'write_command' of git://github.com/Schoonology/jekyll:
  fixup! Implemented `write` command.
  Implemented `write` command.
Default to 'draft' instead of 'post'
Set path more generally in Write command.
Use String#empty? instead of String==''
Fixes and tidying
Completely refactored into a new class.