OSX: fix compilation with 10.7 SDK

Recent work in the OS X parts of the code started using clang's support for
Obj-C's support for Literals and Subscripting. These particular language
features remove a lot of boilerplate code and allow to interact with
collections as consicely as one would do in scripting languages like Ruby or
Python.

Even if these are compiler features, Subscripting needs some runtime support.
This is provided with libarclite (coming with the compiler), but we need to
add the proper method definitions since the 10.7 SDK headers do not include
them. That is because 10.7 shipped before this language features.

This will cause some warnings when compiling with the 10.7 SDK because the
commit also redefines BOOL to make autoboxing/unboxing of BOOL literals to
work.

If you need to test this for whatever reason on 10.8, just pass in the correct
SDK to configure's extra cflags:

  ./configure --extra-cflags='-mmacosx-version-min=10.7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.7.sdk'

Fixes #117
ildetect.sh: env vars support
ildetect.sh: better interlace detection range
encode_lavc: simplify encoding status output; remove percentage
command line: allow --o= to disable encoding (i.e. empty string file name)
encoding: use --start for ratios, etc.

Note: this currently only works for formats without pts resets. Other
formats will ignore this code.
ildetect.sh: skip needlessly going through vo_lavc

We can now turn off encoding mode by command line and use vo_null
instead.
ildetect.sh: add a quiet mode; verify telecine decision

For quiet mode: ILDETECT_QUIET=1 ildetect.sh ...

Telecine decision (guess by ildetect.so) is verified by retrying the
ildetect run with the pullup filter inserted.
lua 5.2 compatibility

One could enable some compatibility stuff in Lua 5.2 to get lua_cpcall,
but our emulation (mp_cpcall) is nicer anyway.
w32_common: refactor mouse button code, handle mouse up events

Instead of sending a single event on click, send both down and up
events.
w32_common: prevent that window dragging and osc interfere
Merge remote-tracking branch 'mpv/master' into lua_experiment
fix merge