Start v0.14.4-dev
Clarify release instructions
Clarify the consequences of using System.at_exit
Remove deprecated features and deprecate soft ones
Merge pull request #2526 from alco/at-exit-doc

Clarify the consequences of using System.at_exit
Update bitstring syntax in base.ex
Merge pull request #2528 from alco/base-warnings

Update bitstring syntax in base.ex
Ensure functions in `Kernel.SpecialForms` and `IEx.Helpers` are also auto-completed

Closes #2527
use pure erlang function to judge the erlang version, no shell.
Merge pull request #2530 from qingliangcn/master

use pure erlang function to judge the erlang version, no shell.
Ensure type_to_signature works for all AST variables
Revert "Merge pull request #2530 from qingliangcn/master"

This reverts commit 42875c0b72863aa3f263ad227ffc7c454c001ae6, reversing
changes made to be320880b2231c6933a87fea335612cafbfeea7f.
Updating System.cmd return types
Merge pull request #2531 from jwarwick/system_cmd_type

Updating System.cmd return types
Insert new line after IEx clear message
Optimize String.slice by using binary_part
Merge pull request #2536 from alco/string-slice-speedup

Optimize String.slice by using binary_part
Add linearity notes to Enum.fetch and friends
Improve description of operations that takes linear time
Update doc for GenEvent.stream/2

- GenEvent streams are not two way, so remove language suggesting that
you can notify via the streams.
- Clarify that consumption doesn't start until we enumerate.