descriptive than using doc->index != -1.
Add deprecated macros DOC_IDX_VALID and DOC_IDX in plugindata.h,
which can make porting outside plugins easier; of course, it is
better to rewrite the code to use document pointers.
Use is_valid instead of the DOC_VALID macro when iterating over
documents_array, as there are never NULL pointers in it.


git-svn-id: https://geany.svn.sourceforge.net/svnroot/geany/branches/document-pointer@2704 ea778897-0a13-0410-b9d1-a72fbfd435f5