Fixed #12 - (thanks @petejohanson)

• Added fromFileSafe function
• Added fromTextSafe function

Fixed problems with Option values boxed to null

Move to .NET Standard 2.0

• Added $is-last and $is-not-last values for loops (thanks @otto-geb!)
• Fixed quadratic complexity of loops (thanks @otto-geb!)

Fix incorrect deletion of the end "param" tag (Issue #8)

• Fix for literals with spaces (Issue #4)
• Supports using numbers in templates (Issue #5)
• Improved parsing logic

Added support for direct tuples destructuring in fs-for cycle

Bugfix for parsing piped functions with literals

Output now keeps original case (XAML support)