API-Level Installation UI

Some new functionalities:
* dev can now browse lists of existing NDKs, simulators and runtime libraries
* dev can add existing NDK, not detected automatically
* dev can install any remote NDK, symulator or runtime library
* dev can open URL and download PlayBook NDK (MSI)
* dev can remove any installed item (beside NDKs installed by MSI = automtatically detected)
* all installations or removals can be queued with abort support
* installations show progress
* fixed some build system issues

All comments welcome.


![1](https://cloud.githubusercontent.com/assets/475630/3235606/7bd7a552-f0d4-11e3-8d8b-001da503ed34.png)
![2](https://cloud.githubusercontent.com/assets/475630/3235607/7bdceb20-f0d4-11e3-821b-d8a2d3664e30.png)
![3](https://cloud.githubusercontent.com/assets/475630/3235608/7be3367e-f0d4-11e3-9bf5-2e50cf9de72c.png)
![4](https://cloud.githubusercontent.com/assets/475630/3235605/7bd18e9c-f0d4-11e3-97ab-b0ad0e7a9053.png)
![5](https://cloud.githubusercontent.com/assets/475630/3235611/7f71145a-f0d4-11e3-8a72-2eb52e8a5375.png)