fixed two edge case bug in the filesystem loader

* fixed caching when two templates have the same template name but a different namespace
* fixed the error message when a template has a namespace
removed usage of deprecated classes in unit tests
removed usage of deprecated constants
updated CHANGELOG
Don't use array_fill for full array
merged branch Misiur/master (PR #1158)

This PR was squashed before being merged into the master branch (closes #1158).

Discussion
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Don't use array_fill for full array

When last array returned from array_chunk is full, array_fill is called with 0 as num argument, which causes fatal error. Additionally I've changed doc fill parameter, as other types are accepted as well, and added unit test.

Commits
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270c794 Don't use array_fill for full array
updated CHANGELOG
Merge remote-tracking branch 'upstream/master'