Merge pull request #3 from AltNico/develop

update
added function to import/export data, but it does not work perfectly at
the moment...
update "Add Homework" page
add permission to read external storage
moved import/export to own method
do not hardcode directory in /data/data
auto-formatted the whole code with eclipse
combine cutted strings to one, i. e. "hwid"+"_size" to "hwid_size"
Merge pull request #4 from AltNico/develop

Update
Adding a DialogWhenLarge theme for tablets
Fixed the name of the Shared Preferences 

The package name was still hardcoded in the prefs file.
-TableLayout +ButtonBar -"match_parent"

* Since you made it so everything is one line, I switched it to a LinearLayout for simplicity.
* You are allowing 1.6 devices. "match_parent" was added in API 8, so I switched it to "fill_parent" to work.
* Now, the "add" button is pinned to the bottom of the screen, styled as a button bar.
ButtonBar for Gingerbread or lower.

Styled to look like, for example, the Package Installer buttons.
Used in activity_add as
```xml
<include layout="@layout/button_bar" />
```
See the layout-v11 for the Holo style.
ButtonBar for Honeycomb and above.
Added theme for Add dialog
Added tablet theme for Add dialog

The add dialog will show as a dialog on tablets now, because otherwise, it is kinda empty
Replaced "match_parent" with "fill_parent"

For backwards compatibility.
fixed hardcoded height
auto formatted code and fixed version issue
auto-formatted the whole code with eclipse