Docs about various entities that affect graph execution

[stonier]

As introduced by the new ecto::BREAK discussed in #279.

Also removed the redundancies in the install docs (2x install instructions and 2x dependencies) and cleaned the place up a bit.

[v4hn]

leaving this typo aside, +1 to merge this.

side remark:

Otherwise, ecto is still easy to build from source:

Imo the described build process is horrible and not easy at all :D

[stonier]

I agree somewhat about the source install instructions...the described build process is awkward and was definitely confusing to my team mates since nowhere else in ros do they describe installing sources like this.

I get the sentiment though. He (whoever wrote the initial docs?) is describing a very minimal install process for catkin. There doesn't need to be a For ROS Users section since ecto can often be used without any ROS at all. We use catkin for all our development, but use ROS for only about 30% of it.

Changes I would like to make:

• Brief explanation about catkin and links to docs at the start of the install from source page.
• Don't mix instruction styles - i.e. try to stick to instructions on ubuntu w/ catkin
• No pip instructions in the install step (for reference, just pure ubuntu instructions)
• Pip install for breathe in the doc part (no apt-get package for that).
• Use catkin_make instead of pure cmake instructions (it's not a tutorial about how catkin is a wrapper around cmake).

Questions

• Outline the download process using wstool instead of linking CMakeLists.txt and git cloning?

[v4hn]

• Brief explanation about catkin and links to docs at the start of the install from source page.

If this explains that catkin can but does not have to be used with ROS, this would make a For ROS Users section unnecessary.

• Use catkin_make

At least, this would streamline the build instructions with the standard ROS catkin build process, so technically +1.

• Outline the download process using wstool instead of linking CMakeLists.txt and git cloning?

+1 to wstool (this would require wstool in the dependencies though) The CMakeLists.txt is not installed by wstool, but by catkin_init_workspace.

[stonier]

Ach, sorry lads. Accidentally commited from the wrong branch and closed this. @v4hn I did follow up on your comments in 9ebdd37c.

I have a preview copy of the docs as they stand now at http://files.yujinrobot.com/tmp/ecto/index.html.

[v4hn]

Looks good to me,

this leaves #282 before a new ecto release should be pushed.

[vrabaud]

doc got updated and build got triggered, we're good to go.