refactor(sublime pkg control): move install script

- Will need this for other packages to more safely
    ensure package control is setup

SublimeText2.PackageControl/SublimeText2.PackageControl.nuspec

@@ -25,5 +25,6 @@
   </metadata>
   <files>
     <file src="tools\**" target="tools" />
+    <file src="..\core\SublimeHelpers.ps1" target="tools" />
   </files>
 </package>

SublimeText2.PackageControl/tools/ChocolateyInstall.ps1

@@ -1,19 +1,16 @@
+function Get-CurrentDirectory
+{
+  $thisName = $MyInvocation.MyCommand.Name
+  [IO.Path]::GetDirectoryName((Get-Content function:$thisName).File)
+}
+
 try {
   $package = 'SublimeText2.PackageControl'
 
-  # install package control
-  $installPath = Join-Path $Env:ProgramFiles 'Sublime Text 2'
-  $sublimeDataPath = Join-Path ([Environment]::GetFolderPath('ApplicationData')) 'Sublime Text 2'
-  $packagesPath = Join-Path $sublimeDataPath 'Installed Packages'
-  if (!(Test-Path $packagesPath)) { New-Item $packagesPath -Type Directory }
-  $packageControl = Join-Path $packagesPath 'Package Control.sublime-package'
+  $current = Get-CurrentDirectory
+  . (Join-Path $current 'SublimeHelpers.ps1')
 
-  if (!(Test-Path $packageControl))
-  {
-    # http://wbond.net/sublime_packages/package_control/installation
-    $packageUrl = 'http://sublime.wbond.net/Package%20Control.sublime-package'
-    Get-ChocolateyWebFile -url $packageUrl -fileFullPath $packageControl
-  }
+  Install-SublimePackageControl
 
   Write-ChocolateySuccess $package
 } catch {