[transitivity] and [symmetry] use [_@_] and [_^]
Also create coq/ide in configure
Merge pull request #500 from JasonGross/configure-hoqide

Also create coq/ide in configure
add more coq/ symlinks to .gitignore
Merge pull request #491 from JasonGross/trans-concat

Since @andrejbauer agrees, I am pulling this one.
Unfold [transitivity] and [symmetry] in the corresponding tactics