(Part 2) Use proper naming for handles/functions that represent EwkView

(Part 2) Use proper naming for handles/functions that represent EwkView

Commit [1] cleaned up most of the "evas_object" occurances inside tizen_src (but outside
ewk layer). This commit is follow up of [1], which replaces rest of the occurances with
ewk_view/EwkView inside ewk layer. Read [1]'s commit message for more details.

[1] c65e88bc0c05def7e76e229beb506f2638034024

Also, cleans up unused/redundant functions.

Change-Id: I2f95f491e2dc72ebbb719df2efdccf1e2a229cb7
Signed-off-by: Gajendra N <gajendra.n@samsung.com>