util: check if re2 works before using it (issue 3964)

run-tests: backout 4f32747879d1 line endings change It made the windows buildbot sad.

hgweb: highlight line which is linked to at comparison view

hgweb: change highlighted line color to be different from 'inserted' color This changes line highlight color from a fain yellow (#ffff99) to a faint blue (#bfdfff), because yellow color is used in comparison view for inserted lines. This new color is okay for people with different forms of color blindness (tested with a simulator): a) this color looks quite different from other used backgrounds b) text doesn't lose distinction on this color

convert: fix bad conversion of copies when hg.startrev is specified The 'copynode' was looked up in self.keep as if it was a changeset node. It is however a filelog node, and self.keep would thus fail if it actually looked at its parameter ... which it only did if a startrev was specified. Instead we now don't check the copy node - we don't have to. It must have been copied from one of the parents, and we already check whether one of the parents have the copy source. We could perhaps use linkrev to see if the corresponding changeset was converted ... but that would sometimes be wrong. The existing test of this was wrong - now it is better, but it seems like it exposes a 'log' issue.

test-convert-hg-startrev: fix test for copy removal on missing parent The test assumed that 'b' was missing just because the changeset that introduced 'b' wasn't converted ... but 'b' was also not removed before the start revision, and the parent was thus not missing at all. Instead we introduce a file 'f' in rev 0 and remove it in rev 1 so the copy source really doesn't exist in the repo that is converted from rev 1.