nbconvert tests

# nbconvert tests

## Overview

Suite of automated nose tests for nbconvert
**Accompanies #3607**

## Tasks

- [ ] Travis CI

### App tests

- [x] Does help show when no notebooks are specified?
- [x] Does glob work?
- [x] Does glob into a subdirectory work?
- [x] Does explicit notebook listing work?
- [x] Does glob, then explicit notebook listing work?
- [x] Does explicit notebook listing and then glob work?
- [x] Does default config work?
- [x] Does custom config via commandline override directory config?
- [x] Does the format specified from the commandline override format in default config?

### Exporters

- [x] Try export by name with a name we know doesn't exist, do we get the right error?
- [x] export_by_name a filename
- [x] export_by_name a notebook node
- [x] export_by_name a filestream
- [x] export using an exporter instance
- [x] export using an exporter class
- [x] Try to export with resources, does it still work?
- [x] Try to export without an exporter, does it through the right error?
- [x] Try to construct an exporter
- [x] Try to construct a basichtml exporter
- [x] Try to construct a fullhtml exporter
- [x] Try to construct a latex exporter
- [x] Try to construct a markdown exporter
- [x] Try to construct a python exporter
- [x] Try to construct a reveal exporter
- [x] Try to construct a rst exporter
- [x] Try to construct a sphinx_howto exporter
- [x] Try to construct a sphinx_manual exporter
- [x] Export using an exporter
- [x] Export using a basichtml exporter
- [x] Export using a fullhtml exporter
- [x] Export using a latex exporter
- [x] Export using a markdown exporter
- [x] Export using a python exporter
- [x] Export using a reveal exporter
- [x] Export using a rst exporter
- [x] Export using a sphinx_howto exporter
- [x] Export using a sphinx_manual exporter
- [x] Try enabling the extract figure transformer, verify figures are extracted
- [x] Try adding a custom transformer via the extra transformers list (instance)
- [x] Try adding a custom transformer via the extra transformers list (class type)
- [x] Try adding a custom transformer via the extra transformers list (dotted object name)
- [x] Try adding a custom transformer via the public method
- [ ] Try adding a custom filter via traitlet
- [ ] Try adding a custom filter via the public method

### Filters

- [x] DataTypeFilter

#### ansi

- [x] remove_ansi
- [x] ansi2html
- [x] ansi2latex

#### highlight

- [ ] highlight
- [ ] highlight2latex

#### latex

- [ ] escape_latex
- [ ] rm_math_space

#### markdown

- [ ] markdown2html
- [ ] markdown2latex
- [ ] markdown2rst

#### strings

- [ ] wrap
- [ ] strip_dollars
- [ ] rm_fake
- [ ] python_comment
- [ ] get_lines

### Templates

- [ ] Fuzzy compare an exported notebook using the basichtml template
- [ ] Fuzzy compare an exported notebook using the fullhtml template
- [ ] Fuzzy compare an exported notebook using the latex template
- [ ] Fuzzy compare an exported notebook using the markdown template
- [ ] Fuzzy compare an exported notebook using the python template
- [ ] Fuzzy compare an exported notebook using the reveal template
- [ ] Fuzzy compare an exported notebook using the rst template
- [ ] Fuzzy compare an exported notebook using the sphinx_howto template
- [ ] Fuzzy compare an exported notebook using the sphinx_manual template
- [ ] Strict compare the results of a custom template

### Transformers


- [ ] coalescestreams
- [ ] svg2pdf
- [ ] csshtmlheader
- [ ] extractfigure
- [ ] latex
- [ ] revealhelp
- [ ] sphinx

### Writers

- [ ] files
- [ ] stdout
- [ ] debug