File en-/decryption with Streams

This adds en-/decryption which can handle big files by using Streams.
Additionally a test file is added to test this function (only ~100 Bytes).
#150 is closed by this.
First #146 and #161 have to be merged, then I need to rebase^^
Wouldn't something like this also work without the fence problem:
```
while (inputStream.available() > 0) {
    int readBytes = inputStream.read(temp, 0, SYMM_ALT_READ_SIZE_BYTE);
    fileOutput.write(symmetricAltCipher.update(temp, 0, readBytes));
}
fileOutput.write(symmetricAltCipher.doFinal());
```
or
```
while ((inputStream.read(temp, 0, SYMM_ALT_READ_SIZE_BYTE)) > 0) {
    fileOutput.write(symmetricAltCipher.update(temp, 0, readBytes));
}
fileOutput.write(symmetricAltCipher.doFinal());
```