Make BatInt.pow raise Invalid_argument for negative exponents.

This goes for BatInt.Safe_int.pow as well. The documentation is updated to
reflect the change, and tests are implemented.
Merge pull request #274 from jathd/fix-batint-pow

Make BatInt.pow raise Invalid_argument for negative exponents.
Update FAQ to add help on "unbound module batteries" error.
Fix #275: typo in META; found by madroach
Remove escape_arg_win; already implemented under win32 as Filename.quote
Fix #276: handle multiple \r, more tests
Base min function on Pervasives.compare
Merge pull request #278 from VictorNicollet/master

Using `Pervasives.compare` to compute minimum
qtest.mll now uses the Arg module for command-line parsing
(cherry picked from commit 8f67650a76144f59ffb54a16a7a6ce54744e9634)

Conflicts:

	qtest/qtest.mll
add to 'qtest' the option to include a preamble-file, rather than just preamble code
(cherry picked from commit 4bb1e40dade49e764f9d985742cc94f2c70f28dd)
qtest: add option "--run-only <fun>" so that only the tests involving this function are actually generated.
qtest: reorganise arguments list alphabetically (as it used to be), and change the layout to something closer to the pre-Arg help page's look. Added back defaults, which I think should appear in a help page.
qtest: correct the order in which the statements of a single test are generated; they used to be reversed.
Implement Option.filter
qtest: --shuffle option to randomise test order (now used for Batteries).
Note: submodules where injection appears are *not* randomized at all,
because the test pragmas may then be dependant upon the injection pragmas.
Also some minor aesthetic cleanups. Also note that until then the tests
were executed in reverse order... now they will be executed in the order
of definition, unless shuffled. (actually, the suite was built in reverse
order, and then executed in reverse... so the two reverses cancelled
each other out. I think it's better to spend a few microseconds doing two
List.rev than to leave that kind of tripwires lurking around in the code.)
Merge pull request #279 from VictorNicollet/master

`List.filter` equivalent for options
Update broken link to tutorial 'for programmers'
Merge pull request #280 from semperos/doc-fix

Update broken link to tutorial 'for programmers'
Add BatFloat.is_finite + tests
Merge pull request #283 from hcarty/float-additions

Add BatFloat.is_finite + tests