Stop use hardcoded virtualenv name in python commands.

This allow users specify virtualenv throw third party extensions,
and not depend on name conventions.
Globally ignore tox cache directory.
Merge pull request #265 from proofit404/hotfix/python-support

Stop use hardcoded virtualenv name in python commands.
Small doc fix
Minor doc fixes
Merge pull request #271 from nonsequitur/better

Minor doc fixes
Make projectile-replace faster if possible

Will try to use ag, ack, git grep, and grep, in that order.

Closes #262.
Merge pull request #269 from shosti/ag-project-replace

Use ag with projectile-replace if possible
Declare ack-and-a-half-arguments prior to use

The autoload on the ack-and-half call loads the library, unfortunately
until that has happened ack-and-a-half-arguments is not declared so this
code will fail without a require on ack-and-a-half first.

This solves it by simply declaring the variable first. I'm not quite
sure how this works if defcustom has already loaded a value for this
variable, but this shouldn't override existing values.

The other approach is to change the fboundp call to
(require 'ack-and-a-half nil 'no-error). That doesn't remove the free
variable error on ack-and-a-half-arguments though.
Merge pull request #275 from dgtized/declare-ack-and-a-half-args

Declare ack-and-a-half-arguments prior to use
Use lexical scoping by default
Fix a typo
Don't bind dynamically the name of the project for projectile-switch-project-hook
Need to require ack-and-a-half for it to work

I guess I didn't test this as well as I should have previously. It would
appear that defvar without a value still leaves it as void. Since the
function references the arguments before autoload brings in
ack-and-half, it's used in projectile while still void.
Fix git-grep to work in Windows.
[Fix #277] Correct the cl-lib dep in helm-projectile
Fix lein project type detection
Merge pull request #273 from bling/master

Fix git-grep to work in Windows.
Merge pull request #276 from dgtized/fix-ack-for-real

Need to require ack-and-a-half for it to work
Fix build