Questions: Flirting

This girl i'm friends with came up to me and give me a high five but didn't let my hand go. She grabbed it for like 10 seconds while we're talking. I tried to pull my hand back but she kept grabbing it.

I also noticed that she doesn't mind if i touch her. She lets me hug her and rest my arm on her shoulders and stuff like that.

Could this be a sign she's interested?

I would appreciate some helpful responses please.

Today (30/09/15) I was approached by an older woman colleague (early 50s) who asked if she could borrow my car cleaning equipment to clean her car to which I offered to do it for her. She seemed taken aback at first but soon agreed to let me do it and seemed pleased that I offered.

Later on after I had finished, she was walking past my office and spotted me and came over to thank me for doing it and asked if I had done inside the car too to which I said I had.

At that moment she then sighed (in a good relief way) and then put her arm around me as in a hug embrace and her head on my chest (we were both standing at this point) for around 3-4 seconds.

Later on she said thank you for doing my car 'my darling'.

Does this mean anything as in flirting or am I getting the wrong end of the stick? The photo is just how the hug embrace was.

Thanks