Update Json.4.5.7
Correction of https://github.com/Twitterizer/Twitterizer/issues/19

Signed-off-by: rodrigopalhares <superpalhares@gmail.com>
Build Twitterizer2 with 4.0 profile
Don't sign the assembly
Reference Newtonsoft.Json source project
Fixed casing of System.Configuration reference
Fixed parsing media entities
Merge branch 'newtonsoft_4.5.8_fix' into rebase/twitterizer-2.4.1
Fixed build on Mono 3.0 with gmcs