Fix fourtech epslevel

Fixes #960. 

Additionally, changes were made to the way epslevel is updated in the ```fourtech``` methods ```diff```, ```times```, ```qr```, and  ```cumsum``` to match what is done in ```chebtech``` for these methods.  

The 2/3 power check for the tail in ```classicCheck``` has also been changed to 1 to also match what is done in ```chebtech/classicCheck```.

Tolerances in test were also updated so that everything passes.