Running in batch mode dont give the right canvas/scale

```
- What steps will reproduce the problem?
1. Run in GUI mode and observe the canvas/scale (default to 150.0)
2. Run again but in batch mode and observe the canvas/scale: it will be now 1.0
(which is the default value for session.location.refscale)

- What is the expected output? What do you see instead?

I expect to see the scale that I have configured or the default value of 150.0,
but instead I see always 1.0

- What version of the product are you using? On what operating system?

4.6svn7 (20140403)

- Please provide any additional information below.

I am working in a extension to mobility basic range model for wlan, which use
the distance (in meters) between nodes and some propagation model (e.g. FSPL)
to verify the existence of conectivity, instead of only pixel distance. I know
about EMANE but it is very complex for what I need and it dont give me the
information that I need.

I could find that CORE/TCL dont read some configs when running in batch mode,
specially (api.tcl):

...
proc sendCanvasInfo { sock } {
global curcanvas

if { ![info exists curcanvas] } { return } ;# batch mode
set obj "location"

set scale [getCanvasScale $curcanvas]
...

From the above code, the scale is never set when running in batch mode.

Some possible solutions are as following: i) use different scales in GUI and
batch mode, but this is very bad for the emulation; ii) use GUI scale of 1.0
would be a work around, but the emulation area will grow a lot; iii) another
workaround would be create a new scale config parameter in my extension, but it
will be a duplication of configuration. For now, I'm just using iii.

What do you guys think?
```

Original issue reported on code.google.com by `italova...@gmail.com` on 5 Aug 2014 at 1:57