Fix StyleParseUtils' splitLength() to support "px" units
Add parameter "epsilon" to core.UnitTestRunner.shouldBe(), for fuzzy number comparison
Add StyleParseUtilsTests
Use absolute tolerance for unit test number comparison

relative tolerance is hard to do with an expected value of 0
Merge pull request #567 from kossebau/fixStyleParseUtilsIgnoringPx

Fix StyleParseUtils ignoring "px" as unit
Moved file arguments for Closure Compiler

On Windows I was beginning to hit the command line limit on the size of
the argument string which prevented me from compiling. Closure Compiler will
process any flags passed in through the --flagfile option so I have moved
all the --js file arguments there.
Merge pull request #571 from satsuper/args-fix

Workaround for the command line argument length limit on Windows
Use mono-spaced font for line-break detection tests

The line detection tests rely on text wrapping at a particular point in
order to function. Enforcing a monospace font and using the em value for
paragraph width measurements ensures (relatively) consistent behaviour
across different systems, irrespective of the system fonts available.
Merge pull request #575 from peitschie/line-tests

Use mono-spaced font for line-break detection tests
Suppress manual task processing to prevent skewing of benchmark figures

Manually processing the redraw tasks vastly affects the current benchmark
results, dwarfing impacts from most other subsystems. Disabling this for
now to aid tuning of non-UI components.
Extract common concept for retrieving text content associated with a step
Re-align downgrade whitespace logic to match upgrade whitespace

Downgrade whitespace now follows the same logic as upgrade, and will
downgrade a whitespace element just to the left of the step, and to the
left of the next step to the right.

Using step iterators instead of position iterators also fixes some failing
operation tests by ensuring one step to the right is checked irrespective
of how many positions there are between steps.