Add some Solidity snippets

snippets/solidity-mode/console_log

+# -*- mode: snippet; require-final-newline: nil -*-
+# name: console_log
+# key: clo
+# --
+console.log(${1:var}, "$1");$0

snippets/solidity-mode/function_internal

 # -*- mode: snippet; require-final-newline: nil -*-
 # name: function_internal
-# key: fi
+# key: fin
 # --
 function ${1:name}(${2:arg}) internal {
     $0

snippets/solidity-mode/import

 # name: import
 # key: im
 # --
-import "${1:version}";
+import "${1:file}";
 $0

snippets/solidity-mode/uint256

+# -*- mode: snippet; require-final-newline: nil -*-
+# name: uint256
+# key: ui
+# --
+uint256 $0