Feature proposal: saving current request setup under named alias

This is great package, thanks for sharing your work!

As I’ve been using it couple of days I noticed that it’s quite inconvenient, having to repeatedly change request settings every time I want to send different request.
The option of saving current state of request would solve the problem.

Given this output of httpie post:

http://127.0.0.1:3000/api/oauth/token> http --form --style native POST http://127.0.0.1:3000/api/oauth/token user_id==value client_id=value client_secret=value grant_type=password password=test  username=testuser1 Content-Type:application/x-www-form-urlencoded

We could use eg.: http://127.0.0.1:3000/api/oauth/token> alias getToken

which would save the request under getToken keyword. Later, we could call getToken request and optionally overwrite any req options like so:

http://127.0.0.1:3000/api/oauth/token> getToken username=testuser2 password=test2

[eliangcs]

@fogine I think exec is a great idea! A user can use source to override context partially, while exec can be used to replace the current context with a new one.

The file path should be relative to the current working directory. When we have shell command support (WIP in #61), we can do something cool like:

> value=="a very long string"
> env > ./out.txt

# Compute sha1 hash of 'value' in shell, and assign back to querystring parameter 'value_sha1'
> value_sha1==`cat ./out.txt | grep value | sed "s/^value==//g" | sha1sum`

[fogine]

@eliangcs, I completely forgot that it was me who has started using the enum module. I replaced the enum for a regular class. Now it works, thanks very much!