delete! -> pop!

fixing 
```

WARNING: delete!(d::Dict,key,default) is deprecated, use pop!(d,key,default) instead.
 in on_message_complete at /home/rene/.julia/HttpServer/src/RequestParser.jl:101
```
Merge pull request #11 from rened/patch-1

delete! -> pop!
Update REQUIRE to slide on patch level
Fixes overly-relaxed REQUIRE
remove Pkg.fixup from .travis.yml
added julia 0.2- to REQUIRE file
Removed ".jl" typo in "cd" and rephrased
Merge pull request #14 from rened/patch-2

Removed ".jl" typo in "cd" and rephrased
Merge pull request #15 from rened/master

Changes for serving binary files
Update HttpServer.md

* remove references to other packages; that should be dealt with in a higher-level summary separate from individual packages.
* add some explanatory comments to the example
Update HttpServer.md

Add reference to HttpCommon.
Fix unit tests