Hough standard transmission for findLines()

Resolves Issue #151 

Now in findLines() Hough standard and probabilistic transmissions. Toggle between them using 'useStandard' argument. Default transmission remain probabilistic, so nobody's code will be broken.

Hough probabilistic transmission:
```python
lines = img.findLines()
```
![Untitled](https://f.cloud.github.com/assets/3843082/386999/fe8f834e-a6b5-11e2-9f40-bfebc0a28dd3.png)

Hough standard transmission:
```python
lines = img.findLines(useStandard=True)
```
![Untitled2](https://f.cloud.github.com/assets/3843082/387003/1be5b580-a6b6-11e2-8f3f-613bd3cca7f5.png)