This addon enables you to
straighten out multiple connected-edge-snakes between their endpoints.
Documentation
First go to User Preferences->Addons and enable the StraightenPlus addon
in the Mesh category.
Go to EditMode, select one or more connected-edges-snakes (you can
straighten several at the same time).
The vertices will be straightened out between the endpoints. Choose
amount of straightening with slider.
Restrict axis toggle restricts straightening to the view plane.
ENTER or leftmouse to end operatio and keep values, rightmouse or ESC to
cancel.
If you wish to hotkey StraightenPlus:
In the Input section of User Preferences at the bottom of the 3D View >
Mesh section click 'Add New' button.
In the Operator Identifier box put 'mesh.straightenplus'.
Assign a hotkey.
Save as Default (Optional).