Retain indentation level of previous line.

Before, if GetCoffeeIndent didn't detect the need to indent / outdent,
it would return -1. Now it returns the indentation level of the previous
line if it exists. This makes for more convenient behavior when typing
'cc' on an empty line below an indented line, and matches how other
vim extensions such as javascript behave.
Don't wrap GetCoffeeIndent

According to the help pages, indentexpr restores the cursor itself
Dox
Don't need to check if less than zero

prevnonblank and GetPrevNormalLine don't return anything less than zero
If continuing a comment, keep the indent level (#74)
Make CoffeeCompile per-buffer instead intead of global (#75)

Now buffers can open their own separate CoffeeCompile watchers.

Horizontal and vertical splitting was also changed to make the CoffeeCompile
buffer end up closer to its source buffer.
detect coffee from shebang line
Style tweaks
Add support for B in binary literals

Per coffee-script commit:
jashkenas/coffee-script@6d33a2e1a0f79ff587352bf2679579e809cbb7db
Add coffee_make_compiler to set a compiler path (#78)
Dox
Update copyrights
Use single quotes
Add CoffeeLint command
Fix a tiny bug in the docs (spotted by pathogen's doc loader)
Remove unnecessary functions
Replace coffee_make_compiler with coffee_compiler

coffee_make_compiler is deprecated already! But the new option is also used by
CoffeeCompile.

Now an error is shown if the compiler executable doesn't exist.
Add coffee_linter option

Also check if the coffeelint executable exists
Add new octal literals

Per coffee-script commit
jashkenas@coffee-script/4372138fdd0ae20d5427f0ab368dc794eac5e361
Dox