Change "Install" to "Build" in headings
Add side remarks to install recommendations

- resources for python installations other than Python(x,y)
- extending PATH for CMake
- using MAD-X <latest revision> versus <latest version>
- multiple extraction steps for madx source code
- using cmd.exe instead of enhanced console
- fix link location for prebuilt binaries
Make it easier to avoid one of the build errors

The 'Unable to find vcvarsall.bat' error will almost certainly occur if
following the install recommendations.
Add info on how to handle "-mno-cygwin" error
Remove "Occurs" and "Reason" remarks

These were not really informative or helpful.
Refer to OS-specific instructions in Dependencies section

The OS specific instructions contain additional remarks how the
dependencies should best be installed and a reference to the dependency
section anyway. So it's better that the user does not first install
dependencies on his own and afterwards finds out that there is a better
way.
Use the seealso directive
Remove unnecessary patch

The suggested patch was for a code version that already fixed the
problem in question.
Fix typo in README
Link to github.io pages for documentation
Merge pull request #79 from pymad/improve-doc

Fix some documentation issues