Initial stab at asyncio integration
Refactor expect code
Expose async as parameter for expect
Fix EOF in async on Linux
support timeout in async expect
Expand tests for async expect
Check already read data before async reading more
Expose async parameter for expect_exact
Document asyncio integration
Stop testing on Python 2.6 and 3.2

We will drop support for these Python versions in Pexpect 4.0
Merge pull request #69 from takluyver/asyncio

asyncio integration for expect