Added first version of table-based valve.

This is for #205.
Moved examples of dampers and valves into separate Example folders.

This is for #205. The change has been done as there are an increasing number of examples for the valves, and hence it is better to separate them from the damper examples.
Revised valve model.

This is for #205.
Revised valve documentation. Added record for table-based valve.

This is for #205.
Updated example.

This is for #205.
Added test model for valve and revised valve code.

This is for #205.
Corrected malformed html

This is for #205
Added unit test for valve for #205.
Added input keyword to phi in valve base class.

This is for #205.
Added documentation.

This is for #205.
Corrected typo.

For #205.
Updated release notes with the new valve model.

This is for #205.
Moved parameter l to base class.

This is needed for replaceable models as are used in the 3-way valve
model to work.
This is for #205.
Moved homotopyInitialization

Removed  in PartialTwoPortInterface the parameter
homotopyInitialization as it is not used in that class. Added it to
other classes that require it.
This is part of #205 revision.
Merge pull request #207 from lbl-srg/master

Merge expansion vessel to valve branch.
Removed instantiation of BaseIconLow which is not used in the Annex60 library.
Removed unrequired extends statement.
Improved documentation.

This is for #205.
The previous documentation used the same k for two different quantities.
Improved documentation.

This is for #205.
Corrected wrong html syntax.

This is for #205.