feat(core): EncodingHelpers from posh-git

- Used to ensure we read/write text files properly

core/EncodingHelpers.ps1

@@ -0,0 +1,17 @@
+# Adapted from http://www.west-wind.com/Weblog/posts/197245.aspx
+function Get-FileEncoding($Path)
+{
+  $bytes = [byte[]](Get-Content $Path -Encoding byte -ReadCount 4 -TotalCount 4)
+
+  if (!$bytes) { return 'utf8' }
+
+  switch -regex ('{0:x2}{1:x2}{2:x2}{3:x2}' -f $bytes[0..3])
+  {
+      '^efbbbf'   { return 'utf8' }
+      '^2b2f76'   { return 'utf7' }
+      '^fffe'     { return 'unicode' }
+      '^feff'     { return 'bigendianunicode' }
+      '^0000feff' { return 'utf32' }
+      default     { return 'ascii' }
+  }
+}