Update versions
Change minVersion to Firefox 17

We need at least Firefox 12, and no one should really be using anything
below Fx17 ESR.
Fix things so that they (hopefully) don't break under latest Q
Revert "Add type="application/javascript;version=1.8" to all JS script tags (for now)"

This reverts commit 35b1c168584ea59d2c2a236d94717eca99751ec6.

Not necessary since Mozilla bug 830665 is fixed
Revert "Load as JS 1.8, to avoid throwing on "for each" for now"

This reverts commit b938ce5fdd2f4ab72adf71e9b6fd18633bdeae6b.

Not necessary since Mozilla bug 830665 is fixed