New stroke-linecap style option with a VML alternative. For #1643.

src/layer/vector/Path.SVG.js

@@ -80,6 +80,9 @@ L.Path = L.Path.extend({
 			} else {
 				this._path.removeAttribute('stroke-dasharray');
 			}
+			if (this.options.linecap) {
+				this._path.setAttribute('stroke-linecap', this.options.linecap);
+			}
 		} else {
 			this._path.setAttribute('stroke', 'none');
 		}

src/layer/vector/Path.VML.js

@@ -82,6 +82,9 @@ L.Path = L.Browser.svg || !L.Browser.vml ? L.Path : L.Path.extend({
 			} else {
 				stroke.dashStyle = '';
 			}
+			if (options.linecap) {
+				stroke.endcap = options.linecap.replace('butt', 'flat');
+			}
 
 		} else if (stroke) {
 			container.removeChild(stroke);

src/layer/vector/Path.js

@@ -18,6 +18,7 @@ L.Path = L.Class.extend({
 		stroke: true,
 		color: '#0033ff',
 		dashArray: null,
+		linecap: null,
 		weight: 5,
 		opacity: 0.5,