Also add it to the changelog for 1.8

Git warns when it finds "whitespace errors". This commit gets
rid of these whitespace errors for code and adoc files.

Also remove the description of behavior for trailing non-numeric characters.
It's likely this will become a parse error in the future so better leave it
as unspecified for now.

Fixes #80.

Fixes #61.

Also add PUGIXML_COMPACT to pugiconfig.hpp

Fixes #43.

Slightly reword format_indent description.

Ensure that all the necessary cleanup is performed in case the allocation fails
with an exception - files are closed, buffers are reclaimed, etc.

Any test that triggers a simulated out-of-memory condition is ran once again
with a throwing allocation function. Unobserved std::bad_alloc count as test
failures and require CHECK_ALLOC_FAIL macro.

Fixes #17.

This eliminates one more hardcoded version from the repo, yay!

It's almost done; the only remaining issue is that some section titles are too long.

Also minor wording fixes.

Users no longer need to #include "pugixml.cpp"

Mostly added correct quotation to changelog.