remove executable flag on soem files
Split exporter in to for ipynb->ipynb
some trailing whitespace
import baseexporter in init
Exporter -> TemplateExporter / BaseExporter
fix 1 test
renamed:    exporter.py -> template_exporter.py
renamed:    baseexporter.py -> exporter.py
renamed:    template_exporter.py -> templateexporter.py
Rebase changes made by hand
Check if class is an instance of Exporter, not TemplateExporter
Fixed Travis, missing import in export.py
@MinRK fix suggestions
renamed:    test_exporter.py -> test_templateexporter.py
Added tests for nb2nb Exporter
Also fixed some small things in template exporter tests.
Merge pull request #4175 from jdfreder/exporterbase

add base Exporter class above TemplateExporter