Merge pull request supercollider#1371 from supercollider/topic/fix-do…

…c-modified-warnings

ide: Fix triggering of doc modified signal

ide: Fix build, missing SC_BuildString function.

travis temp

travis: fix error when building a tag

also, fix tabs on gitter webhook (I think...)

Last commit before pull request supercollider#1334, which switches ma…

…ster to QT5.

Commit of pull request supercollider#1334, which switches master to QT5.