Allow node version up to 0.10.20

Node version 0.10.20 passes tests.

```
> fileupload@0.2.4 test /home/zdwolfe/src/fileupload
> node ./node_modules/pliers/pliers-cli.js qa

[32m09:40:41[39m [pliers] Running task: qa
[32m09:40:41[39m [pliers] Running task: test
[32m09:40:41[39m [pliers] Executing node ./test/tests


  fileupload
    #createFileUpload()
      middleware
        ◦ creates the upload dir if it doesnt exist: [2K[0G        ✓ creates the upload dir if it doesnt exist (56ms)
        ◦ moves file to the correct location: [2K[0G        ✓ moves file to the correct location (38ms)
        ◦ works for more than one file input in a form: [2K[0G        ✓ works for more than one file input in a form 
        ◦ works for arrays of files: [2K[0G        ✓ works for arrays of files 
        ◦ is tolerant of no files being uploaded: [2K[0G        ✓ is tolerant of no files being uploaded 
      #put()
        ◦ successfully puts a file when given a file path: [2K[0G        ✓ successfully puts a file when given a file path 
        ◦ returns the correct file mime type: [2K[0G        ✓ returns the correct file mime type 
        ◦ returns the correct file size: [2K[0G        ✓ returns the correct file size 
        ◦ moves files to the correct location: [2K[0G        ✓ moves files to the correct location 
        ◦ returns an error if file doesnt exist: [2K[0G        ✓ returns an error if file doesnt exist 
        ◦ stores the file in a folder named as an md5 hash of the file: [2K[0G        ✓ stores the file in a folder named as an md5 hash of the file 
      #get()
        ◦ returns the file when passed a file object: [2K[0G        ✓ returns the file when passed a file object 
        ◦ returns the file when passed a file path: [2K[0G        ✓ returns the file when passed a file path 
        ◦ returns an error if file does not exist: [2K[0G        ✓ returns an error if file does not exist 
        Streams
          ◦ writes file data to a stream: [2K[0G          ✓ writes file data to a stream 
      #delete()
        ◦ deletes the file when passed a file object: [2K[0G        ✓ deletes the file when passed a file object 
        ◦ deletes the file when passed a file path: [2K[0G        ✓ deletes the file when passed a file path 


  17 tests complete (263 ms)

Finished { total: 17, pass: 17, fail: 0 }
[32m09:40:42[39m [pliers] Completed task: test
[32m09:40:42[39m [pliers] Running task: lint
[32m09:40:42[39m [pliers] Executing jshint .
lib/fileupload.js: line 2, col 5, Redefinition of '_'.

1 error
[32m09:40:42[39m [pliers] exec('jshint .') returned with with code 2
npm ERR! weird error 2
npm ERR! not ok code 0
```