Android patch 20140623

Things to improve in later versions (or now if someone knows a better way):
  * wchar conversion
  * Hack detection
  * Better way to replace builtin formspecs, maybe add Lua API functions
  * Other things you find in there ;-)

### Building

#### Debug:
```
cd build/android
make
<Answer questions>
```
#### Release:
```
<prepare keystore>
cd build/android
make release
<Answer questions>
<enter password when prompted>
```
There's a timestamp kept to check for it. So download is only done if there ain't any code. Additionally except of curl for those targets there's not a single file to use as dependency.