Ahodges/doc/relnotes20141021

@mhoeber , @catong , @srpearce please take a look -- anything else to add? 
@explorerleslie , @shnayder ?
It's only capitalized in headings - and, actually, "protein builder" shouldn't be capitalized either (see http://edx.readthedocs.org/projects/edx-partner-course-staff/en/latest/exercises_tools/protein_builder.html). Problem and tool type names aren't capitalized. Are you seeing this capitalized outside of headings?