Replace delete in favor of setting to undefined to prevent V8 deoptimization.
Prevent V8 "assignment to parameter in arguments object" deoptimizations.

Some getter-like functions still need fixing, but this might require a fix in Straps.js first.
Merge branch 'refs/heads/paperscript-refactoring' into v8-optimizations
Merge branch 'refs/heads/master' into v8-optimizations

Conflicts:
	src/core/Base.js
	src/style/Color.js
fix error in cario installation documentation
Use changes in latest Straps.js to remove as many hidden parameters as possible.

Hidden parameters through arguments[] are bad news for JS optimizer engines.
Merge branch 'refs/heads/master' into v8-optimizations
Remove the need for arguments[0] in bounds getters.
Remove need for arguments[1] in Item#transform()
Move Curve#getLength(from, to) to Curve#getPartLength(from, to).

Clears up the Curve#getLength() getter and removes the need for accessing arguments[]
Rearrange Base.read argument sequence.

options are used more often than length.
Remove unused arguments._read value and rename _index to __index.
Prevent overriding of global variables with undefined values during development.
Fix small error in PathStructure example.
Update PathStructure example to code from website.
Replace delete in favor of setting to undefined to prevent V8 deoptimization.
Filter out loop statements in operator overloading code, to optimize loop execution speed.
Use the same filtering for UpdateExpression and AssignmentExpression.
Prevent unnecessary beans from being created.
Minor PaperScript clean-ups.