stablerange: use last recently used caching for revisions associated to ranges This does not make things faster but at least it make them able to finish on large repositories.

stablerange: report progress more often in slow case For small repositories the time spent in progress was problematic. However on large repository it quickly becomes negligible, so we add a way to detect this case and report more often in this case.

template: update successors template output Use templatekw._hybrid as return value for precursor template, it's nicer and easier to play with than returning a formatted string.

test: extract metaedit tests into test-metaedit.t test file The metaedit command deserver it own test file and this shave of 15% of the runtime of test-evolve.t one of our longest tests.

template: update precursors template output Use templatekw._hybrid as return value for precursor template, it's nicer and easier to play with than returning a formatted string.

template: skip "fate" in test output when empty This should clarify the test output a bit.