Minor CMake improvements

* Use the empty ELSE(), ENDIF(), ENDMACRO(), etc. syntax since this improves
readability and requires less typing.
* Use FIND_PACKAGE() instead of INCLUDE().
* Use the value of CMAKE_COMMAND variable instead of cmake, since this works
even if cmake is not in the PATH.

Put the version string into config.h

Also make it possible to set the version using the LEMON_VERSION environment
variable, and use the hg revision as version string in case this variable is
unset.

Fix the check for the 'long long' type

Change the label of the html project in Visual Studio

Generate and install LEMONConfig.cmake

Add tools/CMakeLists.txt to the tarball

Rename documentation install folder from 'docs' to 'html'

Remove duplications from doc/CMakeLists.txt

Suppress MSVC warnings using pragmas (#295)

Add artificial addNode() function to the arc/edge set classes

Avoid Intel C++ Compiler warnings

Disable Visual Studio warning C4503

Add lemon/config.h.cmake to the tarball

Resolve GCC-4.4 warnings & fix ambiguous op=() in graph_components.h

Update NEWS file

Extend min cost flow test file + check dual costs (#291)

Fix the GEQ/LEQ handling in NetworkSimplex + improve doc (#291)

- Fix the optimality conditions for the GEQ/LEQ form.
- Fix the initialization of the algortihm. It ensures correct
solutions and it is much faster for the inequality forms.
- Fix the pivot rules to search all the arcs that have to be
allowed to get in the basis.
- Better block size for the Block Search pivot rule.
- Improve documentation of the problem and move it to a
separate page.

Merge

Remove bits/base_extender.h, which is not used at all (#288)

Move list and edge sets to the graph module (#290)

Merge

Change the explanation of the acronym LEMON (#289)

Change Graph::Edge -> Graph::Arc inheritance to conversion (#283)

Change Undirector::Edge -> Undirector::Arc inheritance to conversion (#283)

Fix the faulty merge of unify-sources.sh in [586b65073025]

Doc fixes for lgf-gen (#282)

Merge

Merge