Partial unzipping to save memory

1. Made code work on uint8arrays as well as strings. Discourage making
of new strings as much as possible. In some cases I pass strings with
bounds (start and end) rather than make new ones - e.g. .uncompress for
STORE in jszip.js. In others I build strings up using .join rather than
concatenating with += which can make a new string each time e.g.
JSZip.utils.string2binary. Some browsers are smart enough to optimise
these cases anyways but others aren't.

Plus strings take 2x as much space as UTF-8 arrays (at least for
english). Loading in the original zip file as an arraybuffer and making
it into a uint8array saves that memory which is significant for large
zips (75MB+)

2. Add a flag to options (noinflate) that doesn't automatically inflate
the zip if true

3. Exposed zipEntries in the JSZip object. This gives a handle to call
the new readLocalFile function on the entry after the JSZip object is
initialised.

4. readLocalFiles and readLocalFile in ZipEntries now take an optional
streamFunction parameter. This is a function that parses bytes as they
are returned from the inflate methods. Using this parameter we can write
code that returns only part of each decompressed file, useful for csv
files or for sampling. If not defined then jszip-inflate.js uses the
original inflation code which returns everything.

5. Ran against test suite. All changes reported ok, no failures.

6. I haven't added a test case as such as success is more about how much
memory it uses. I added a subdirectory in test called big which can be
played about with.

Download an example from
http://dumps.wikimedia.org/other/pagecounts-raw/2013/2013-01/. Must be
rezipped as a .zip rather than a .gz and the test can then be run. This
is a 75MB file that unzips to a 290MB log file of 6.3M+ rows of 4
columns. ZipParse has a function that reads in 2 columns for every 10th
row.

All browsers on Windows 7 (32-bit)
Chrome 27 - fastest - 223M working mem on process
Firefox Aurora 23.0a2 - ok - 365M working mem
Safari 5.1.7 - ok - webkit2webprocess - 431M working mem
IE9 - takes an absolute age but gets there - finishes on 700M working
mem, peaking at 925M, of course here we have to string the original zip
file
opera - stalls
added screenshot of output