more efficient math

/!\ this is only correct if x is always comprised between 0 and width,
and y between 0 and height
Added majority of widgets to qmldir.
Merge pull request #10 from advancingu/fix/qmldir

Added majority of widgets to qmldir.
declared directly in the diameter property
unnecessary parenthesis removal
Merge pull request #7 from Sheraff/master

more efficient math
Merge pull request #8 from baszczewski/master

Improve the ink animation to make it consistent with material design
First step of refactoring.