Implement the rules for parsing integers as defined by HTML, and use them for canvas.
Handle failure to parse the value of the width and height attributes on canvas elements (fixes #3200).

The remaining failures are due to the tests's use of getComputedStyle.
Unify fontconfig source code so that one branch builds on both linux + android.
Merge pull request #3201 from glennw/fc-platform-fixup

Unify fontconfig source code so that one branch builds on both linux + android
Merge pull request #3205 from Ms2ger/parse-integers

Parse canvas's width and height attributes according to the specification; r=jdm
Implement document.lastModified (fixes #2972, #3127).