allow global task options in gruntfile

[scott-kennedy]

This commit allows global options in a gruntfile and merges them with the existing options for each task. It reduces the amount of duplication needed in the gruntfile when you have multiple tasks that all use the same base options.

Ex gruntfile before:

spriteGenerator: {
    taskOne: {
        compositor: 'gm',
        compositorOptions: {
            compressionLevel: 9
        },
        layout: 'diagonal',
        src: [
            '<%= dirs.root %>/images/icons/*.png'
        ],
        spritePath: '<%= dirs.root %>/images/sprite.png',
        stylesheetPath: '<%= dirs.css %>_sprites.scss',
        stylesheet: 'scss',
        stylesheetOptions: {
            pixelRatio: 2
        }
    },
    taskTwo: {
        compositor: 'gm',
        compositorOptions: {
            compressionLevel: 9
        },
        layout: 'diagonal',
        src: [
            '<%= dirs.root %>/images/icons/blue/*.png'

        ],
        spritePath: '<%= dirs.root %>/images/sprite.png',
        stylesheetPath: '<%= dirs.css %>_sprites.scss',
        stylesheet: 'scss',
        stylesheetOptions: {
            pixelRatio: 2
        }
    }
}

Ex grunfile after:

spriteGenerator: {
    options: {
        compositor: 'gm',
        compositorOptions: {
            compressionLevel: 9
        },
        layout: 'diagonal',
        stylesheet: 'scss',
        stylesheetOptions: {
            pixelRatio: 2
        },
        spritePath: '<%= dirs.root %>/images/sprite.png',
        stylesheetPath: '<%= dirs.css %>_sprites.scss'
    },
    taskOne: {
        src: [
            '<%= dirs.root %>/images/icons/*.png'
        ]
    },
    taskTwo: {
        src: [
            '<%= dirs.root %>/images/icons/blue/*.png'
        ]
    }
}

[coveralls]

Coverage remained the same when pulling 0bedee41ee1026a7baa30c931a1ec94c94faf15a on scott-kennedy:allow-global-task-options into 375b918fc07a5f6aab2650ee9daf1d39455133aa on selaux:master.

[selaux]

Great :+1: , can you fix the code style issue then I can merge.

[scott-kennedy]

@selaux, updated the code styling to merge the two vars.

[coveralls]

Coverage remained the same when pulling c0260f47a192277af62e79a0997fb4a731ba048b on scott-kennedy:allow-global-task-options into 375b918fc07a5f6aab2650ee9daf1d39455133aa on selaux:master.