Create clone of numpy.loadtxt

[WarrenWeckesser]

Create the function loadtxt with an API that is compatible with numpy.loadtxt.

API completion tasks

• handle sequences, iterators, generators, etc.--whatever loadtxt can handle (currently read handles a filename or a file-like object)
• converters parameter
• encoding parameter
• parse complex values (e.g. 1.2-3.4j). (Make the complex unit character configurable.)
• unpack parameter
• ndmin parameter
• dtype parameter
• comments parameter
  • one comment string, max 2 characters.
  • multiple comment strings (low priority)
• delimiter parameter
• skiprows parameter
• usecols parameter
• max_rows parameter

Optimization

• Dynamically update data types in a single pass (currently, giving an explicit dtype results in a single pass, and specifying dtype=None results in two passes)