updating test_files submodule
Support for parsing Comments

Comments parts listed in the [Content Types] are parsed.
Sheets's relationships are parsed.
Comments parts are correlated to their corresponding sheets parts.
Comments's contents are added to the ref'ed cells.
Rich text styling properties are currently ignored.

For example:
{
  "!ref": "A1:B3",
  "A1": {
    "v": 1,
    "t": "n"
  },
  "B1": {
    "v": "one",
    "t": "s",
    "r": "one",
    "c": [
      { "a": "Yegor Kozlov",
       "t": [ "Yegor Kozlov:",
              "\r\nfirst cell" ]
      }
    ]
  }
}
Add parsing comment codes into bits/70_xlsx.js

Update test xlsx file to apachepoi_SimpleWithComments.xlsx
Comments maybe contain an empty text tag
Share the code for parsing the rich text and use it to parse the comments.
Update the range of the sheet when creating a cell for the content of its comments
Merge pull request #43 from nerds-odd-e/comment_support

Support for parsing Comments
version bump 0.3.7: comments and coverage

- parsing comments (h/t @kinwahlai, @hmalphettes)
- XLSX.version now exposed in source
- code coverage
- updated SSF to 0.5.2
- updated tests/files
version bump 0.3.8: more formatting

- updated SSF to 0.5.3

tests without baselines now try to generate CSV output
version bump 0.3.9: general format used by default

(when no format or style is found, use general)

Other whitespace cleanup
version bump 0.3.10: xlsm support

different workbook content type, same representation
README updates [ci skip]
version bump 0.4.0: very basic XLSB support

subfiles reshuffled (XLSB and XLSX/XLSM content separated)
version bump 0.4.1: more XLSB + cleanup

- updated ssf to 0.5.4
- cleaned up CSV string output
- added CSV tests (from test_files)
- passes lint
- inlineStr actually parses <is> block
- more XLSB bits
version bump 0.4.2: using jszip module on node

- updated test_files
- new dependency in node: jszip
travis ignore node 0.8 due to jszip bug

See https://github.com/Stuk/jszip/issues/84 for more info
version bump 0.4.3: shared strings and formatting

- XLSB basic support for number formats
- removed extraneous Strings table element
- formatting xml tags (rich_stress_test)
- updating test_files to 20130130
version bump 0.5.0: changes to cell interface

Cell object stores the formatted text in the `.w` field
- Raw format and types are preserved in the `.t`, `.v` fields
- Accessors have been updated to use the field

updates for older OOXML:
- ECMA-376 makes reference to old sstItem shared string item
- [MS-XLSX] xmlns for workbook
xlsb browser fix
version bump 0.5.1: field reorg

- cell.r holds the raw rich text, cell.h now holds the html
  (version 0.5.0 cell.raw -> cell.r, cell.r -> cell.h)
- similar changes to comments and XLSB generation
- removed some unused binary methods