Bump version: v0.1.12
Bump version: v0.1.12

[Add]
 - Support for `delete` statement in `do` blocks for deleting object properties
 - New method `mayBeUndefined` to handle `undefined` values
 - Minify for core files

[Fix]
 - Issue with consecutive standalone `do` blocks

[Modify]
 - Change the way `import` works

cleanlang/clean,cleanlang/clean,cleanlang/clean