go vet and lint

* Naming
    * If this is not some OpenPGP standard I follow rule that `DES` should be
      upper case as it is abreviation and `Triple` should be camel-case as it
      is normal word hence `TripleDES`
    * rename `errors2` -> `errorsPGP`
* long lines
    * https://github.com/golang/go/wiki/CodeReviewComments#line-length
    * I bit improved long lines based on my folding
    * reuse type in definition if possible i.e. `a string, b string, c string` -> `a,b,c string`
    * `if long_statetent(); err!=nil {` -> `long_statement;↵ if err!=nil {`
    * spaces around operators (e.g. `a + b` -> `a+b`)
* removing empty lines on start and end of scope
* comments
    * on all exported functions
    * start with function name
* import:
    * order in alphabet
    * separate native, golang.org/x/ and our libs

glide.lock

@@ -58,3 +58,5 @@ testImports:
     version: 34c6fa2dc70986bccbbffcc6130f6920a924b075
     subpackages:
     - assert
+  - name: github.com/golangci/golangci-lint
+    version: 901cf25e20f86b7e9dc6f73eaba5afbd0cbdc257