v0.2.20-buffer

Added addFileFromBuffer().

v0.2.20b

CMake: allow to specify an XML library.

If we don't then we get some undefined symbols XML-related methods (e.g., _xmlCreatePushParserCtxt).

v0.2.18

Update VERSION.txt

v0.2.17

 - same submodule commands

v0.2.15

- bump version

v0.2.13b

Renamed the library to [lib]combine.

With `[lib]Combine`, a CMake file called `[lib]Combine-static-config.cmake` gets generated. Such a CMake file cannot be found on a case-sensitive system (since that kind of filename should be all lower case). Instead, a CMake file called `[lib]combine-static-config.cmake` should be generated.