Adding 'btnSubmit' ID to contact form button so it disables when clicked

Minor accessibility fixes

update package.json

update gulpfile.js

Adding 'btnSubmit' ID to contact form submit button as expected by contact_me.js. Fixes issue where user can click submit button repeatedly thinking nothing has happened causing multiple emails to be sent.

Changed the name to an h1, for easier page navigation and better SEO.

The for attribute programmatically links the labels to their matching
form fields.

Alternate text is useful for screen reader users, to describe the
content of the image link.

A skip navigation link allows screen reader and keyboard-only users to
quickly skip the navigation menu. This one is visually hidden and
transitions in on focus. Helps site meet WCAG 2.0 SC 2.4.1 Bypass Blocks

Keyboard-only users need a visual indicator of focus when navigating a
page. This change meets WCAG 2.0 SC 2.4.7: Focus Visible.

This text, marked with the sr-only class, provides a text alternative
for users using a screenreader or custom style sheet

Adding gulp-filter that enables modification I suggested in the gulpfile.

Adding gulp-filter and using it on less files that way (excluding mixins and variables files) enable a developer to add custom less to the less folder and be sure that they will be transformed to css by gulp.

Run less before minift-css

Sometimes minify-css can run before less since they are parallel tasks
Make minify-css wait for the completion of less so the freelancer.min.css file is always generated.
Otherwise gulp needs to be run twice to ensure an updated *.min.css file

removed dependency on Bootswatch flatly theme and repalced it wtih custom code, added a vendor directory so third party plugins are now separate from theme files

Don't let the user lose scroll control when a '.page-scroll a' is cli…

When ‘.page-scroll a’ is clicked, the user cannot stop the document
from scrolling until the document has reached the selected section.
This commit allows the user to stop a scroll anytime they want.