V2.0 update

## Features 

### Open
* Now returns the activeDocument after opening the file.

### JSLayer()
* Removed semicolon from output.

### Document
* Added FullName() which returns path to the .psd file.
* Changed Filename() to DumpFile(), as Filename was misleading.
* Dump function now saves the file as well,
to help reduce the frequency of de-syncs.
* Dump function now saves json files alongside the .psds
instead of in a separate data folder- encountered issues when using
the package as a module in go 1.11beta2.
* Added Save()

## Testing
* Added TestDocument_Save
* Added TestDocument_Dump

## Misc.
* Renamed pkgpath to pkgPath, to better fit go's standards.

## Fixes
* DoAction now runs correctly.

artlayer.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
-	"strings"
 
 	"github.com/sbrow/ps/runner"
 )
@@ -211,8 +210,7 @@ func (a *ArtLayer) SetVisible(b bool) error {
 	case false:
 		log.Printf("Hiding %s", a.name)
 	}
-	js := fmt.Sprintf("%s.visible=%v;",
-		strings.TrimRight(JSLayer(a.Path()), ";"), b)
+	js := fmt.Sprintf("%s.visible=%v;", JSLayer(a.Path()), b)
 	if byt, err := DoJS("compilejs.jsx", js); err != nil {
 		log.Println(string(byt))
 		return err