wrong branch, big sorry

This reverts commit e77d08a6.

Added functions ChainTypeFromString, ChainTypeFromString, StringFromChainType for handling ChainType, with tests and documentation.

the vector export helper had to be moved to geom because otherwise the geom export depends on base whose headers might not be staged at the time of the compilation of the geom exports

Instead of only checking for the validity of the impl class, the view
classes now also check if the view data is valid. This improves debugging in
cases (when the trying to access, for example, an AtomView whose EntityView has
been deleted.

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2674 5a81b35b-ba03-0410-adc8-b2c5c5119f08

GetGeometricStart()/GetGeometricEnd() has been deprecated and
will be removed sooner or later.

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2501 5a81b35b-ba03-0410-adc8-b2c5c5119f08

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2438 5a81b35b-ba03-0410-adc8-b2c5c5119f08

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2395 5a81b35b-ba03-0410-adc8-b2c5c5119f08

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/branches/new_shell@2368 5a81b35b-ba03-0410-adc8-b2c5c5119f08

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2354 5a81b35b-ba03-0410-adc8-b2c5c5119f08

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@2101 5a81b35b-ba03-0410-adc8-b2c5c5119f08

-adding GetAtomList to chainhandles and enabling .atoms property
-fixing already defined getprop in windows in entitity_view

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@1886 5a81b35b-ba03-0410-adc8-b2c5c5119f08

git-svn-id: https://dng.biozentrum.unibas.ch/svn/openstructure/trunk@1742 5a81b35b-ba03-0410-adc8-b2c5c5119f08