Change to polygongraph instead of polygon in roomtool

The polygon room tool used a convoluted process for determining what the
user actually wants to draw. I have changed to the polygon graph
instead, which makes the checks easier and restricts the user a bit
less. In the process however I found a serious problem with my handling
float, so everything needed to change to margin compares (which I of
course should have done in the beginning. Guys, take the warning
seriously and don't ignore it for ten years like I did. It will come
back to haunt you.. apparently) instead of direct equality.

1 files changed, 2 insertions, 1 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 23c17be..0a8e040 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,4 +15,5 @@ svgtypes = "*"
 xmltree = "*"
 pretty_env_logger = "*"
 log = "*"
-thiserror = "*"
\ No newline at end of file
+thiserror = "*"
+float-cmp = "*"
\ No newline at end of file