Change all internal imports to search user headers.
Change use of `float` to `CGFloat`.
Change `ceilf` usage to `ceil` instead.
Merge pull request #54 from rastersize/normalize-header-import

Normalize the import of other Butter headers in Butter headers
Change drawingRectForBounds to have its Y ceiled when dH > 0.

Change-Id: I172f71456196defd3dfbc081be6c1e2b0b578a86
Merge pull request #55 from rastersize/fix-implicit-floating-point-precision-loss

Fix implicit floating point precision loss
Fix improper nil check
Merge pull request #59 from tonyarnold/patch-1

Fix improper nil check
import BTRLabel to fix build issue in BTRPopUpButton
Merge pull request #60 from ButterKit/fix-popup-imports

Fix imports in BTRPopUpButton
fix a reference cycle in the popup button
Merge pull request #61 from ButterKit/fix-cycle

Fix a reference cycle
move most common initializers to static functions
move BTRImageView's common initializer to a static function, fix bug
Merge pull request #62 from ButterKit/namespacing

Namespacing
Fix build when prefix header is disabled.
Merge pull request #63 from wjk/fix-build

Fix build when prefix header is disabled.
Remove old comment on BTRTextField.
Merge remote-tracking branch 'upstream/master' into purge-update-state

Conflicts:
	Butter/BTRSecureTextField.m
Change name of common init function for secure text field.

- So that the naming matches that used in the `BTRTextField`
implementation.
- Should have no actual consequences for the code.