Fix right aligned cropping for CJK

For example,

    set viewcolumns={name}..,{}

could:

 * Print one more character position.
 * Fail due to assertion.
Fix column draw bug caused by CJK fix

Fix mainly lacked starting offset of the previous column.

Thanks to Daniel Dettlaff (a.k.a. dmilith).
Merge branch 'fix-cropping-broken-by-cjk-fix'

Fix column draw bug caused by CJK fix.  It mainly lacked starting
offset of the previous column.

Thanks to Daniel Dettlaff (a.k.a. dmilith).

Fix right aligned cropping for CJK (e.g. viewcolumns={name}..,{}
could print one more character position or fail due to assertion).