SAN FRANCISCO - Twitter on Wednesday set out to weave itself into mobile applications with a free ‘Fabric’ platform to help developers build better programs and make more money. Twitter chief executive Dick Costolo touted Fabric as ‘the future of mobile software development’ while unveiling the platform at the one-to-many messaging service’s first conference for makers of applications for smartphones or tablet computers. Fabric consists of software tools to tackle challenges such as stability and distribution of applications as well as streamlining user log ins and placing ads.  The move could build Twitter functions directly into new mobile apps.