Add a spec for $! inside at_exit{ }
Always allow at_exit handlers access to $!

Prior to this change only SystemExit's were made available in at_exit.

(git diff -w)
Avoid changing the process title when initializing $0
Merge pull request #1858 from eregon/program_name

Avoid changing the process title when initializing $0
Removed fake __ENCODING__.
Remove implementation detail from Encoding.asciicampat_encoding spec.
Added 1.9.3 specs for Encoding.find.
Removed unnecessary Encoding.asciicompat_encoding spec.

Encoding.asciicompat_encoding returns nil if the Encoding is ascii compatible.
If an Encoding *is* returned, that Encoding is ascii compatible by definition.
Hence, this spec is already covered.
Fixed transcoder extract script to pick up missing transcoders.
Added Encoding.asciicompat_encoding.
Added spec for String#force_encoding(nil).
String#encode shouldn't force_encoding to nil.
Check for exceptions in fallback when inlining polymorphic caches.
Added Encoding::Converter#convpath.
Remove useless typedef
Add tags like 1.9 mode because on some linux versions FFI can bind lchmod
Appendix B - Reading List, spanish translation done.
Rubinius systems, spanish translation done
Fix BlockArgument bytecode generation
Rework using the utf8_limits to use an explicit return value

We depended here on it being signed for the return value, but for 32 bit
systems we need it to be a uint32_t for the correct limits. This changes
it to use an explicit return whether we succeeded or not and store the
result in a separate variable.

Fixes #1864