Use package AbaqusReader.jl (#127)

Source code related to read and parse ABAQUS .inp files is now living in
it's own repository `AbaqusReader.jl` and in this commit we cleanup the
same files from this repository.

- add AbaqusReader to .travis.yml because it's not registered package yet
- initialize Mesh from AbaqusReader.jl dict
- remove ABAQUS tests and files moved to AbaqusReader.jl
- remove references to old module Abaqus
- move ABAQUS code to preprocess.jl (what is left)
- close issue #122
- close issue #55

docs/src/index.md

@@ -6,6 +6,7 @@
 ```@meta
 DocTestSetup = quote
     using JuliaFEM
+    using JuliaFEM.Preprocess
 end
 ```
 
@@ -15,7 +16,9 @@ Add here.
 
 ## Functions
 
-Add here.
+```@docs
+JuliaFEM.Preprocess.create_surface_elements
+```
 
 ## Index